CONTENTS

.Bf -symbolic
The
svc_*
and
clnt_*
functions described in this page are the old, TS-RPC
interface to the XDR and RPC library, and exist for backward compatibility.
The new interface is described in the pages
referenced from
rpc(3).
.Ef

These routines allow C programs to make procedure
calls on other machines across the network.
First, the client calls a procedure to send a
data packet to the server.
Upon receipt of the packet, the server calls a dispatch routine
to perform the requested service, and then sends back a
reply.
Finally, the procedure call returns to the client.

Routines that are used for Secure
RPC( DES
authentication) are described in
rpc_secure(3).
Secure
RPC
can be used only if
DES
encryption is available.

void

auth_destroy AUTH *auth

A macro that destroys the authentication information associated with
auth.
Destruction usually involves deallocation of private data
structures.
The use of
auth
is undefined after calling
auth_destroy.

AUTH *

authnone_create

Create and return an
RPC
authentication handle that passes nonusable authentication
information with each remote procedure call.
This is the
default authentication used by
RPC.

Create and return an
RPC
authentication handle that contains
Unix
authentication information.
The
host
argument
is the name of the machine on which the information was
created;
uid
is the users user ID;
gid
is the users current group ID;
len
and
aup_gids
refer to a counted array of groups to which the user belongs.
It is easy to impersonate a user.

Call the remote procedure associated with
prognum,
versnum,
and
procnum
on the machine
host.
The
in
argument
is the address of the procedures argument(s), and
out
is the address of where to place the result(s);
inproc
is used to encode the procedures arguments, and
outproc
is used to decode the procedures results.
This routine returns zero if it succeeds, or the value of
.Vt enum clnt_stat
cast to an integer if it fails.
The routine
clnt_perrno
is handy for translating failure statuses into messages.

Warning: calling remote procedures with this routine
uses
UDP/IP
as a transport; see
clntudp_create
for restrictions.
You do not have control of timeouts or authentication using
this routine.

Like
callrpc,
except the call message is broadcast to all locally
connected broadcast nets.
Each time it receives a
response, this routine calls
eachresult,
whose form is:

bool_t eachresult caddr_t out struct sockaddr_in *addr

where
out
is the same as
out
passed to
clnt_broadcast,
except that the remote procedures output is decoded there;
addr
points to the address of the machine that sent the results.
If
eachresult
returns zero,
clnt_broadcast
waits for more replies; otherwise it returns with appropriate
status.

Warning: broadcast sockets are limited in size to the
maximum transfer unit of the data link.
For ethernet,
this value is 1500 bytes.

A macro that calls the remote procedure
procnum
associated with the client handle,
clnt,
which is obtained with an
RPC
client creation routine such as
clnt_create.
The
in
argument
is the address of the procedures argument(s), and
out
is the address of where to place the result(s);
inproc
is used to encode the procedures arguments, and
outproc
is used to decode the procedures results;
tout
is the time allowed for results to come back.

void clnt_destroy CLIENT *clnt

A macro that destroys the clients
RPC
handle.
Destruction usually involves deallocation
of private data structures, including
clnt
itself.
Use of
clnt
is undefined after calling
clnt_destroy.
If the
RPC
library opened the associated socket, it will close it also.
Otherwise, the socket remains open.

CLIENT *

clnt_create char *host u_long prog u_long vers char *proto

Generic client creation routine.
The
host
argument
identifies the name of the remote host where the server
is located.
The
proto
argument
indicates which kind of transport protocol to use.
The
currently supported values for this field are
"udp"
and
"tcp".
Default timeouts are set, but can be modified using
clnt_control.

Warning: Using
UDP
has its shortcomings.
Since
UDP -based RPC
messages can only hold up to 8 Kbytes of encoded data,
this transport cannot be used for procedures that take
large arguments or return huge results.

bool_t

clnt_control CLIENT *cl u_int req char *info

A macro used to change or retrieve various information
about a client object.
The
req
argument
indicates the type of operation, and
info
is a pointer to the information.
For both
UDP
and
TCP,
the supported values of
req
and their argument types and what they do are:

CLSET_TIMEOUT

.Vt struct timeval Ta set total timeout

CLGET_TIMEOUT

.Vt struct timeval Ta get total timeout

Note: if you set the timeout using
clnt_control,
the timeout argument passed to
clnt_call
will be ignored in all future calls.

CLGET_SERVER_ADDR

.Vt struct sockaddr_in Ta get servers address

The following operations are valid for
UDP
only:

CLSET_RETRY_TIMEOUT

.Vt struct timeval Ta set the retry timeout

CLGET_RETRY_TIMEOUT

.Vt struct timeval Ta get the retry timeout

The retry timeout is the time that
UDP RPC
waits for the server to reply before
retransmitting the request.

bool_t clnt_freeres CLIENT *clnt xdrproc_t outproc char *out

A macro that frees any data allocated by the
RPC/XDR
system when it decoded the results of an
RPC
call.
The
out
argument
is the address of the results, and
outproc
is the
XDR
routine describing the results.
This routine returns one if the results were successfully
freed,
and zero otherwise.

void

clnt_geterr CLIENT *clnt struct rpc_err *errp

A macro that copies the error structure out of the client
handle
to the structure at address
errp.

void

clnt_pcreateerror char *s

prints a message to standard error indicating
why a client
RPC
handle could not be created.
The message is prepended with string
s
and a colon.
A newline is appended at the end of the message.
Used when a
clnt_create,
clntraw_create,
clnttcp_create,
or
clntudp_create
call fails.

void

clnt_perrno enum clnt_stat stat

Print a message to standard error corresponding
to the condition indicated by
stat.
A newline is appended at the end of the message.
Used after
callrpc.

void clnt_perror CLIENT *clnt char *s

Print a message to standard error indicating why an
RPC
call failed;
clnt
is the handle used to do the call.
The message is prepended with string
s
and a colon.
A newline is appended at the end of the message.
Used after
clnt_call.

char *

clnt_spcreateerror char *s

Like
clnt_pcreateerror,
except that it returns a string
instead of printing to the standard error.

Bugs: returns pointer to static data that is overwritten
on each call.

char *

clnt_sperrno enum clnt_stat stat

Take the same arguments as
clnt_perrno,
but instead of sending a message to the standard error
indicating why an
RPC
call failed, return a pointer to a string which contains
the message.

The
clnt_sperrno
function
is used instead of
clnt_perrno
if the program does not have a standard error (as a program
running as a server quite likely does not), or if the
programmer
does not want the message to be output with
printf,
or if a message format different from that supported by
clnt_perrno
is to be used.

Note: unlike
clnt_sperror
and
clnt_spcreateerror,
clnt_sperrno
returns pointer to static data, but the
result will not get overwritten on each call.

char *

clnt_sperror CLIENT *rpch char *s

Like
clnt_perror,
except that (like
clnt_sperrno)
it returns a string instead of printing to standard error.

Bugs: returns pointer to static data that is overwritten
on each call.

CLIENT *

clntraw_create u_long prognum u_long versnum

This routine creates a toy
RPC
client for the remote program
prognum,
version
versnum.
The transport used to pass messages to the service is
actually a buffer within the processs address space, so the
corresponding
RPC
server should live in the same address space; see
svcraw_create.
This allows simulation of
RPC
and acquisition of
RPC
overheads, such as round trip times, without any
kernel interference.
This routine returns
NULL
if it fails.

This routine creates an
RPC
client for the remote program
prognum,
version
versnum;
the client uses
TCP/IP
as a transport.
The remote program is located at Internet
address
addr.
If
addr->sin_port
is zero, then it is set to the actual port that the remote
program is listening on (the remote
rpcbind(8)
service is consulted for this information).
The
sockp
argument
is a socket; if it is
RPC_ANYSOCK,
then this routine opens a new one and sets
sockp.
Since
TCP -based RPC
uses buffered
I/O,
the user may specify the size of the send and receive buffers
with the
sendsz
and
recvsz
arguments;
values of zero choose suitable defaults.
This routine returns
NULL
if it fails.

This routine creates an
RPC
client for the remote program
prognum,
version
versnum;
the client uses
UDP/IP
as a transport.
The remote program is located at Internet
address
addr.
If
addr->sin_port
is zero, then it is set to actual port that the remote
program is listening on (the remote
rpcbind(8)
service is consulted for this information).
The
sockp
argument
is a socket; if it is
RPC_ANYSOCK,
then this routine opens a new one and sets
sockp.
The
UDP
transport resends the call message in intervals of
wait
time until a response is received or until the call times
out.
The total time for the call to time out is specified by
clnt_call.

Warning: since
UDP -based RPC
messages can only hold up to 8 Kbytes
of encoded data, this transport cannot be used for procedures
that take large arguments or return huge results.

This routine creates an
RPC
client for the remote program
prognum,
on
versnum;
the client uses
UDP/IP
as a transport.
The remote program is located at Internet
address
addr.
If
addr->sin_port
is zero, then it is set to actual port that the remote
program is listening on (the remote
rpcbind(8)
service is consulted for this information).
The
sockp
argument
is a socket; if it is
RPC_ANYSOCK,
then this routine opens a new one and sets
sockp.
The
UDP
transport resends the call message in intervals of
wait
time until a response is received or until the call times
out.
The total time for the call to time out is specified by
clnt_call.

This allows the user to specify the maximum packet size
for sending and receiving
UDP -based RPC
messages.

This routine creates an
RPC
client for the local
program
prognum,
version
versnum;
the client uses
Unix Ns -domain
sockets as a transport.
The local program is located at the
*raddr.
The
sockp
argument
is a socket; if it is
RPC_ANYSOCK,
then this routine opens a new one and sets
sockp.
Since
Unix Ns -based RPC
uses buffered
I/O,
the user may specify the size of the send and receive buffers
with the
sendsz
and
recvsz
arguments;
values of zero choose suitable defaults.
This routine returns
NULL
if it fails.

int

get_myaddress struct sockaddr_in *addr

Stuff the machines
IP
address into
addr,
without consulting the library routines that deal with
/etc/hosts.
The port number is always set to
htons PMAPPORT.
Returns zero on success, non-zero on failure.

struct pmaplist *

pmap_getmaps struct sockaddr_in *addr

A user interface to the
rpcbind(8)
service, which returns a list of the current
RPC
program-to-port mappings
on the host located at
IP
address
addr.
This routine can return
NULL.
The command
"rpcinfo-p"
uses this routine.

A user interface to the
rpcbind(8)
service, which returns the port number
on which waits a service that supports program number
prognum,
version
versnum,
and speaks the transport protocol associated with
protocol.
The value of
protocol
is most likely
IPPROTO_UDP
or
IPPROTO_TCP.
A return value of zero means that the mapping does not exist
or that
the
RPC
system failed to contact the remote
rpcbind(8)
service.
In the latter case, the global variable
rpc_createerr
contains the
RPC
status.

A user interface to the
rpcbind(8)
service, which instructs
rpcbind(8)
on the host at
IP
address
addr
to make an
RPC
call on your behalf to a procedure on that host.
The
portp
argument
will be modified to the programs port number if the
procedure
succeeds.
The definitions of other arguments are discussed
in
callrpc
and
clnt_call.
This procedure should be used for a
"ping"
and nothing
else.
See also
clnt_broadcast.

A user interface to the
rpcbind(8)
service, which establishes a mapping between the triple
(prognum, versnum, protocol)
and
port
on the machines
rpcbind(8)
service.
The value of
protocol
is most likely
IPPROTO_UDP
or
IPPROTO_TCP.
This routine returns one if it succeeds, zero otherwise.
Automatically done by
svc_register.

bool_t pmap_unset u_long prognum u_long versnum

A user interface to the
rpcbind(8)
service, which destroys all mapping between the triple
(prognum, versnum, *)
and
ports
on the machines
rpcbind(8)
service.
This routine returns one if it succeeds, zero
otherwise.

Register procedure
procname
with the
RPC
service package.
If a request arrives for program
prognum,
version
versnum,
and procedure
procnum,
procname
is called with a pointer to its argument(s);
progname
should return a pointer to its static result(s);
inproc
is used to decode the arguments while
outproc
is used to encode the results.
This routine returns zero if the registration succeeded, -1
otherwise.

Warning: remote procedures registered in this form
are accessed using the
UDP/IP
transport; see
svcudp_create
for restrictions.

.Vt struct rpc_createerr rpc_createerr ;

A global variable whose value is set by any
RPC
client creation routine
that does not succeed.
Use the routine
clnt_pcreateerror
to print the reason why.

bool_t svc_destroy SVCXPRT * xprt

A macro that destroys the
RPC
service transport handle,
xprt.
Destruction usually involves deallocation
of private data structures, including
xprt
itself.
Use of
xprt
is undefined after calling this routine.

.Vt fd_set svc_fdset ;

A global variable reflecting the
RPC
service sides
read file descriptor bit mask; it is suitable as a template argument
to the
select(2)
system call.
This is only of interest
if a service implementor does not call
svc_run,
but rather does his own asynchronous event processing.
This variable is read-only (do not pass its address to
select 2 !),
yet it may change after calls to
svc_getreqset
or any creation routines.
As well, note that if the process has descriptor limits
which are extended beyond
FD_SETSIZE,
this variable will only be usable for the first
FD_SETSIZE
descriptors.

.Vt int svc_fds ;

Similar to
svc_fdset,
but limited to 32 descriptors.
This
interface is obsoleted by
svc_fdset.

bool_t svc_freeargs SVCXPRT *xprt xdrproc_t inproc char *in

A macro that frees any data allocated by the
RPC/XDR
system when it decoded the arguments to a service procedure
using
svc_getargs.
This routine returns 1 if the results were successfully
freed,
and zero otherwise.

bool_t svc_getargs SVCXPRT *xprt xdrproc_t inproc char *in

A macro that decodes the arguments of an
RPC
request
associated with the
RPC
service transport handle,
xprt.
The
in
argument
is the address where the arguments will be placed;
inproc
is the
XDR
routine used to decode the arguments.
This routine returns one if decoding succeeds, and zero
otherwise.

struct sockaddr_in *

svc_getcaller SVCXPRT *xprt

The approved way of getting the network address of the caller
of a procedure associated with the
RPC
service transport handle,
xprt.

void svc_getreqset fd_set *rdfds

This routine is only of interest if a service implementor
does not call
svc_run,
but instead implements custom asynchronous event processing.
It is called when the
select(2)
system call has determined that an
RPC
request has arrived on some
RPC
socket(s);
rdfds
is the resultant read file descriptor bit mask.
The routine returns when all sockets associated with the
value of
rdfds
have been serviced.

void svc_getreq int rdfds

Similar to
svc_getreqset,
but limited to 32 descriptors.
This interface is obsoleted by
svc_getreqset.

Associates
prognum
and
versnum
with the service dispatch procedure,
dispatch.
If
protocol
is zero, the service is not registered with the
rpcbind(8)
service.
If
protocol
is non-zero, then a mapping of the triple
(prognum, versnum, protocol)
to
xprt->xp_port
is established with the local
rpcbind(8)
service (generally
protocol
is zero,
IPPROTO_UDP
or
IPPROTO_TCP).
The procedure
dispatch
has the following form:

bool_t dispatch struct svc_req *request SVCXPRT *xprt

The
svc_register
routine returns one if it succeeds, and zero otherwise.

svc_run

This routine never returns.
It waits for
RPC
requests to arrive, and calls the appropriate service
procedure using
svc_getreq
when one arrives.
This procedure is usually waiting for a
select(2)
system call to return.

bool_t svc_sendreply SVCXPRT *xprt xdrproc_t outproc char *out

Called by an
RPC
services dispatch routine to send the results of a
remote procedure call.
The
xprt
argument
is the requests associated transport handle;
outproc
is the
XDR
routine which is used to encode the results; and
out
is the address of the results.
This routine returns one if it succeeds, zero otherwise.

void

svc_unregister u_long prognum u_long versnum

Remove all mapping of the double
(prognum, versnum)
to dispatch routines, and of the triple
(prognum, versnum, *)
to port number.

void

svcerr_auth SVCXPRT *xprt enum auth_stat why

Called by a service dispatch routine that refuses to perform
a remote procedure call due to an authentication error.

void

svcerr_decode SVCXPRT *xprt

Called by a service dispatch routine that cannot successfully
decode its arguments.
See also
svc_getargs.

void

svcerr_noproc SVCXPRT *xprt

Called by a service dispatch routine that does not implement
the procedure number that the caller requests.

void

svcerr_noprog SVCXPRT *xprt

Called when the desired program is not registered with the
RPC
package.
Service implementors usually do not need this routine.

void

svcerr_progvers SVCXPRT *xprt u_long low_vers u_long high_vers

Called when the desired version of a program is not registered
with the
RPC
package.
Service implementors usually do not need this routine.

void

svcerr_systemerr SVCXPRT *xprt

Called by a service dispatch routine when it detects a system
error
not covered by any particular protocol.
For example, if a service can no longer allocate storage,
it may call this routine.

void

svcerr_weakauth SVCXPRT *xprt

Called by a service dispatch routine that refuses to perform
a remote procedure call due to insufficient
authentication arguments.
The routine calls
svcerr_auth xprt AUTH_TOOWEAK.

SVCXPRT *

svcraw_create void

This routine creates a toy
RPC
service transport, to which it returns a pointer.
The transport
is really a buffer within the processs address space,
so the corresponding
RPC
client should live in the same
address space;
see
clntraw_create.
This routine allows simulation of
RPC
and acquisition of
RPC
overheads (such as round trip times), without any kernel
interference.
This routine returns
NULL
if it fails.

SVCXPRT *

svctcp_create int sock u_int send_buf_size u_int recv_buf_size

This routine creates a
TCP/IP -based RPC
service transport, to which it returns a pointer.
The transport is associated with the socket
sock,
which may be
RPC_ANYSOCK,
in which case a new socket is created.
If the socket is not bound to a local
TCP
port, then this routine binds it to an arbitrary port.
Upon completion,
xprt->xp_fd
is the transports socket descriptor, and
xprt->xp_port
is the transports port number.
This routine returns
NULL
if it fails.
Since
TCP -based RPC
uses buffered
I/O,
users may specify the size of buffers; values of zero
choose suitable defaults.

This routine creates a
Unix Ns -based RPC
service transport, to which it returns a pointer.
The transport is associated with the socket
sock,
which may be
RPC_ANYSOCK,
in which case a new socket is created.
The
*path
argument
is a variable-length file system pathname of
at most 104 characters.
This file is
not
removed when the socket is closed.
The
unlink(2)
system call must be used to remove the file.
Upon completion,
xprt->xp_fd
is the transports socket descriptor.
This routine returns
NULL
if it fails.
Since
Unix Ns -based RPC
uses buffered
I/O,
users may specify the size of buffers; values of zero
choose suitable defaults.

SVCXPRT *

svcunixfd_create int fd u_int sendsize u_int recvsize

Create a service on top of any open descriptor.
The
sendsize
and
recvsize
arguments
indicate sizes for the send and receive buffers.
If they are
zero, a reasonable default is chosen.

SVCXPRT *

svcfd_create int fd u_int sendsize u_int recvsize

Create a service on top of any open descriptor.
Typically,
this
descriptor is a connected socket for a stream protocol such
as
TCP.
The
sendsize
and
recvsize
arguments
indicate sizes for the send and receive buffers.
If they are
zero, a reasonable default is chosen.

SVCXPRT *

svcudp_bufcreate int sock u_int sendsize u_int recvsize

This routine creates a
UDP/IP -based RPC
service transport, to which it returns a pointer.
The transport is associated with the socket
sock,
which may be
RPC_ANYSOCK,
in which case a new socket is created.
If the socket is not bound to a local
UDP
port, then this routine binds it to an arbitrary port.
Upon
completion,
xprt->xp_fd
is the transports socket descriptor, and
xprt->xp_port
is the transports port number.
This routine returns
NULL
if it fails.

This allows the user to specify the maximum packet size for sending and
receiving
UDP -based RPC
messages.

bool_t xdr_accepted_reply XDR *xdrs struct accepted_reply *ar

Used for encoding
RPC
reply messages.
This routine is useful for users who
wish to generate
RPC -style
messages without using the
RPC
package.

bool_t xdr_authunix_parms XDR *xdrs struct authunix_parms *aupp

Used for describing
Unix
credentials.
This routine is useful for users
who wish to generate these credentials without using the
RPC
authentication package.

void

bool_t xdr_callhdr XDR *xdrs struct rpc_msg *chdr

Used for describing
RPC
call header messages.
This routine is useful for users who wish to generate
RPC -style
messages without using the
RPC
package.

bool_t xdr_callmsg XDR *xdrs struct rpc_msg *cmsg

Used for describing
RPC
call messages.
This routine is useful for users who wish to generate
RPC -style
messages without using the
RPC
package.

bool_t xdr_opaque_auth XDR *xdrs struct opaque_auth *ap

Used for describing
RPC
authentication information messages.
This routine is useful for users who wish to generate
RPC -style
messages without using the
RPC
package.

.Vt struct pmap ;

bool_t xdr_pmap XDR *xdrs struct pmap *regs

Used for describing arguments to various
rpcbind(8)
procedures, externally.
This routine is useful for users who wish to generate
these arguments without using the
pmap_*
interface.

bool_t xdr_pmaplist XDR *xdrs struct pmaplist **rp

Used for describing a list of port mappings, externally.
This routine is useful for users who wish to generate
these arguments without using the
pmap_*
interface.

bool_t xdr_rejected_reply XDR *xdrs struct rejected_reply *rr

Used for describing
RPC
reply messages.
This routine is useful for users who wish to generate
RPC -style
messages without using the
RPC
package.

bool_t xdr_replymsg XDR *xdrs struct rpc_msg *rmsg

Used for describing
RPC
reply messages.
This routine is useful for users who wish to generate
RPC
style messages without using the
RPC
package.

void

xprt_register SVCXPRT *xprt

After
RPC
service transport handles are created,
they should register themselves with the
RPC
service package.
This routine modifies the global variable
svc_fds.
Service implementors usually do not need this routine.

void

xprt_unregister SVCXPRT *xprt

Before an
RPC
service transport handle is destroyed,
it should unregister itself with the
RPC
service package.
This routine modifies the global variable
svc_fds.
Service implementors usually do not need this routine.